Japanese unexamined patent application publication No. JP-A-2007-42795 (Patent Document 1) describes a related art light output device. For example, Patent Document 1 discloses the related art light output device that is configured to control the output power of a laser diode of a light output unit thereof. It discloses an art to shorten the time required for intensity detection of a laser beam for controlling the output power of a laser diode.
Also, APC (Auto Power Control) has been performed as control of the output power of a laser diode. In the APC, usually the output power is detected and a control voltage signal for controlling the output power to a predetermined value is generated based on the detection result of the output power. The control voltage signal is converted into a drive current of the laser diode by a voltage-current conversion unit.